Method of making slack free wire interconnections
AssigneeKulicke and Soffa Ind. Inc.
InventorsZeev Kirshenboin, Mark B. Soffa
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Abstract
Electrodes and lead-out terminals of semiconductor devices employ fine wire interconnections which require forming into a predetermined configuration. The method of the present invention provides several novel steps in a sequence of steps which causes the interconnection wire to be shaped in an extremely desirable configuration free of slack. The method is characterized by first preforming a portion of the wire in a direction opposite the direction of the desired interconnection and subsequently reforming the preformed portion of wire while the remainder of the interconnection wire is being formed in tension.
Claims24
A method of making slack free fine wire interconnections between a first and a second conductive pad comprising the step of:
- bonding an end of said fine wire to said first conductive pad employing a capillary bonding tool,
- raising said bonding tool vertically upward and horizontally backwards relative to said fine wire to provide two small formed bends in said fine wire,
- raising said bonding tool vertically to pay out a total length of said fine wire slightly greater than the amount required for the final wire interconnection,
- moving said bonding tool horizontally and vertically downward toward said second conductive pad in a first predetermined path which causes a small portion of said wire to re-enter said bonding tool,
- bending said fine wire at the working face of said bonding tool, leaving a length of wire outside of said bonding tool equal to said final wire length of the interconnection,
- moving said bonding tool horizontally and vertically downward toward said second conductive pad in a second predetermined path which creates tension in said fine wire as said bonding tool approaches and touches said fine wire against said second conductive pad, and
- bonding said fine wire under said bonding tool to said second conductive pad to form a slack free interconnection.
A method of making slack free gold wire interconnections between a first and a second conductive pad comprising the steps of:
- bonding a gold ball on a gold wire to said first conductive pad employing a capillary bonding tool,
- raising said bonding tool substantially vertically from said gold ball to pay out a small portion of gold wire from said capillary,
- moving said bonding tool substantially horizontally in a direction away from said second conductive pad to
- form a first bend in said gold wire adjacent said gold ball and
- to form a second bend in said gold wire adjacent the working face of said bonding tool,
- raising said bonding tool substantially vertically from said second bend to pay out a total length of gold wire greater than the amount of gold wire required for the final wire interconnection,
- moving said bonding tool substantially horizontally a small amount without causing movement of said gold wire into or out of said bonding tool,
- moving said bonding tool horizontally and vertically toward said second conductive pad in a predetermined path which causes a small portion of said gold wire to re-enter said bonding tool,
- moving said bonding tool toward said second conductive pad in an arcuate path which converges into the arc of a circle whose radius in equal to the distance between said first and said second conductive pads,
- bonding said gold wire under the face of said bonding tool to said second conductive pad,
- raising said bonding tool a small distance,
- breaking said wire at the bond on said second conductive pad leaving a tail equal in length to said small distance, and
- forming a gold ball on said gold wire tail by heating said tail above the melting temperature of gold.
A method of making a slack free loop in a fine wire interconnection between a first and a second conductive pad of a semiconductor device comprising the steps of:
- bonding said fine wire to said first conductive pad with a capillary bonding tool,
- raising said bonding tool vertically and moving said bonding tool horizontally away from said second conductive pad to provide a first and a second offset bend in said fine wire,
- continuing to raise said bonding tool vertically to pay out a length of fine wire at least twenty-five percent greater than the amount required for said interconnection,
- moving said bonding tool substantially horizontally toward said second conductive pad to initiate bending of said fine wire near said first conductive pad,
- moving said bonding tool horizontally and vertically toward said second conductive pad in a first predetermined path which pushes a portion of said fine wire back into said capillary bonding tool,
- continuing to move said bonding tool horizontally and vertically toward said second conductive pad in a second predetermined path in which said fine wire is bent at the working face of said capillary bonding tool and said offset bend nearest the first conductive pad is continuously reformed and bent toward said second conductive pad, and
- bonding said fine wire to said second conductive pad while maintaining tension in said fine wire interconnection.
Dependencies are inferred from the claim text.